Answer:
11 months
788 disc
Explanation:
Let
x = number of months
Fry's Electronics;
= 920 - 12x
Blu-ray discs:
= 502 + 26x
Equate both equations
920 - 12x = 502 + 26x
920 - 502 = 26x + 12x
418 = 38x
x = 418/38
x = 11 months
number of months = 11
Substitute 11 into any of the equation
Fry's Electronics;
= 920 - 12x
= 920 - 12(11)
= 920 - 132
= 788 disc sold in that months